This invention relates to a disc loading structure for a disc apparatus such as a compact disc player or the like, and more particularly to a disc loading structure for loading a disc such as a compact disc or the like onto a turntable of the disc apparatus.
Recently, the demand on a compact disc (CD) by consumers is highly diversified with rapid spread of the compact disc, leading to the manufacturing and selling of a compact disc of a diameter as small as 8 cm (hereinafter referred to as "8 cm compact disc"), in addition to an existing compact disc of 12 cm in diameter (hereinafter referred to as "12 cm compact disc"). This causes a compact disc player to be required not only to be simplified in construction and exhibit satisfactory operability but to be equally accommodated to both compact discs.
In general, a compact disc player includes a disc loading mechanism for automatically transferring a compact disc to place it on a turntable. Unfortunately, a conventional disc loading mechanism is not constructed so as to be accommodated to a 12 cm compact disc. This causes the playing-back of an 8 cm compact disc to require to use an exclusive adapter, resulting in the operability being highly deteriorated.
In view of the foregoing, the assignee proposed a disc loading mechanism for handling two or more compact discs different in size without using any adapter. The disc loading mechanism is adapted to automatically position a compact disc on a turntable depending upon the size of the compact disc. More particularly, the proposed disc loading mechanism, as shown in FIG. 1, includes a detection sensor group 200 for discriminating the size of a compact disc to be loaded, a solenoid 202, a pair of stopper arms 204, and pivotal-movement regulating plates 206 each for positionally regulating the position of each of the stopper arms 204. The detection sensors of the detection sensor group 200, as shown in FIG. 2, each includes a light emitter 208 and a light receptor 210, which are arranged forward of a disc transfer means 212 so as to correspond to the size of a compact disc. The detection sensors each exhibits a detection mode when a compact disc being transferred overlaps the detection sensor to intercept light emitted from the light emitter 208 toward the light receptor 210. When the sensor group 200 judges predetermined patterns of detection modes of the detection sensors to discriminate the size of the compact disc being transferred toward a turntable 214.
The solenoid 202 is arranged to engage with one of the pivotal-movement regulating plates 206. When the detection sensor group 200 discriminates that a compact disc being transferred or inserted into a disc player is an 8 cm compact disc, the solenoid 202 is energized. This causes the pivotal-movement regulating plate 206 to be restrained, so that the stopper arms 204 are held at an 8 cm compact disc position. Whereas, when the discriminating means or detection sensor group 200 judges that the compact disc is a 12 cm compact disc, the solenoid 202 is de-energized, so that the pivotal-movement regulating plates 206 and stopper arms 204 may be movable. Then, the movement of the compact disc being transferred causes the stopper arms 204 to be moved to and held at a 12 cm compact disc position.
Also, in the conventional disc loading mechanism described above, the detection sensor group detects the completion of insertion of a compact disc into a disc player when the compact disc is positioned on a predetermined position above the turntable. This causes the rotation of the transfer roller 212 to be stopped and the disc to be clamped.
Unfortunately, the conventional disc loading mechanism is substantially increased in manufacturing costs because the detection sensor group constituting the discriminating means and the solenoid are highly expensive. Also, the conventional disc loading mechanism requires a lot of detection sensors for electrically detecting a compact disc, resulting in being complicated in structure and increased in power consumption. In particular, when the disc player is used in a manner to be mounted on a vehicle such as a car, such an increase in power consumption has a possibility of causing a battery used as a power supply for the vehicle to be dead.
Such disadvantages as described above are likewise encountered with a disc player other than the compact disc player, such as a laser disc player which is adapted to handle a plurality of laser discs different in size.